EVAL-AD7616 Standalone Mode

I've purchased an EVAL-AD7616 board to use as a proof of concept for the AD7616. I am required to operate this board in what the documentation refers to as "standalone" mode by using the broken out pins on J5. The device needs to operate in the Software mode described in the AD7616 datasheet. It looks like the proper way to set this up would be to set SER/PAR tied high, SER1W tied low (I only have 1 SPI wire), SCLK/CS/SDOA used as appropriate, the remaining DBx pins tied low, and the RESET pin tied high. I am using 5V for VCC connected through the J9 terminal connector, and 3.3v for VDrive connected through the J8 terminal connector. I have verified that the link positions are in the appropriate place to source power from the terminal connectors, and have verified that LK36-37 are in Position C to set the HW_RNGSELx pins to ground to enable Software mode.

I have two issues:

1) The SER/PAR pin does not appear to be broken out on J5.

2) The chip never appears to power on after VCC and VDrive are applied, as 0 current is drawn through both of these pins (according to my power supply, which I have verified as functional). Additionally, the "PWR-GOOD" LED never lights up.

The documentation for the AD7616 Evaluation board is lacking in description on how to use the board in standalone mode. I would appreciate any help that someone more familiar with the hardware could give me regarding the correct set up for using this eval board in standalone mode with the serial interface. I require using the Evaluation board this way for my proof of concept, and time is not on my side currently. Please advise.

To follow up on this request for assistance, I would like to further clarify the connections I am currently making on the AD7616 evaluation board.

Per the AD7616 documentation, the following needs to be met in order to operate in Software Serial mode.

CHSELx - Connect to DGND

Accomplished by moving LK33, LK34, and LK35 to position C as stated in the evaluation board user guide.

WR/BURST - Connect to DGND

Accomplished by leaving the WR pin on J5 disconnected (it is pulled down to GND by a 100k resistor according to the schematics)

DB15/OS0 to DB13/OS2 - Connect to DGND

Accomplished by leaving the DB15, DB14, and DB13 pins on J5 disconnected (they are pulled down to GND by a 100k resistor according to the schematics)

DB12/SDOA - Connected to MISO of microcontroller

DB11/SDOB - Left floating for serial 1-wire mode

DB10/SDI- Connected to MOSI of microcontroller

DB9 to DB6, DB3 to DB0 - Connect to DGND

Accomplished by leaving disconnected on J5 (they are pulled down to GND by a 100k resistor according to the schematics)

DB5/CRCEN - Connect to DGND

Accomplished by leaving disconnected on J5 (pulled down by 100k resistor according to schematics)

DB4/SER1W - Set to logic 0 for 1 wire serial

Accomplished by leaving disconnected on J5 (pulled down by 100k resistor according to schematics).

HW_RNGSELx - Connect to DGND

Accomplished by setting LK36, and LK37 to Position C

SEQEN - No func, connect to DGND

This is pulled down by a 10k resistor to gnd as indicated by the eval board schematics

SER/PAR - Set to logic 1 for serial

This is accomplished by soldering the SL5 junction on the eval board together to bring the SER/PAR pin to Vdrive.

Now, I believe that I have completed everything that should be required for successful serial operation of the AD7616 evaluation board. My microcontroller is set up to select the communication self test feature in the channel register, then read off the fixed output to verify functionality. I have attached logic analyzer screen shots for two cases.

Case 1) the CS pin disconnected from the evaluation board, and the interaction between my MCU and the AD7616 is recorded (see image below). It is shown that the AD7616 RESET pin is toggled to set configurations that are latched on reset. The first byte shows the channel selection register being addressed for write. The second byte shows the diagnostic channel being written to the register. Afterwards, the conversion start pin is toggled, and 4 bytes are read out that should be the conversion results (only three bytes are pictured). Reminder: in this case, the CS pin is not connected to the evaluation board, so the chip is never enabled for communication.

Case 2) The CS pin is connected to the evaluation board. Everything else is connected as described above, and I should expect to see 0xAAAA and 0x5555 being read as the diagnostic conversion results. What actually occurs, however, is shown below. It appears that the MOSI pin is now being driven low by the AD7616 constantly while CS is low, and no data is latched out on MISO when SCK cycles.

I'm not sure where to proceed from here, and would really appreciate a second set of eyes. Please advise.